The present invention relates to adjustable vehicle seats, in particular to hydraulically adjustable automotive vehicle seats, and to improving seat occupant protection in the event of a vehicle crash or impact.
In order to comfortably accommodate various sizes and shapes of occupants vehicle seats are generally provided with various adjustment mechanisms to adjust the position of the seat within the vehicle and/or move various movable portions of the seat. Typically vehicle seats are provided with fore and aft adjustment, and the seat back is pivotally mounted to a seat bottom cushion such that the angle of the seat back to the bottom cushion of the seat can be adjusted. Other adjustment and adjustment mechanisms may also be provided to, for example, adjust the height of the vehicle seat, angle and tilt of the seat bottom cushion, position of the headrest, and/or the lumber support etc.
The seat adjustment mechanisms whilst allowing the position of the seat and/or seat portions to be adjusted to the desired position also importantly securely lock the seat and/or seat portion in the desired position.
The seat adjustment mechanisms may be manually operable and mechanically locked in place, or increasingly some or all may be power operated and either mechanically or otherwise locked in place. Conventionally various mechanical and for power operated adjustment mechanisms electromechanical arrangements are used. It has also been proposed to use hydraulic adjustment arrangements comprising hydraulic actuator cylinders operatively connected between the movable portions of the seat with suitable control valves to prevent fluid flow and lock the seat position. By suitably arranging the hydraulic actuators and connecting the actuators to a pump supplying pressurised hydraulic fluid in a suitable hydraulic circuit a hydraulically powered seat adjustment can be provided. An example of a powered hydraulic adjustment system is described, for example, in U.S. Pat. No. 5,435,625. An example of a hydraulic seat position locking arrangement is described in U.S. Pat. No. 5,743,591.
There is a general desire within the automotive field to improve the protection provided to an occupant in the event of a vehicle crash or impact. In a vehicle crash or impact significant and violent loads are applied to the vehicle and occupant. These loads, and the resulting violent movement of the occupant under the loads can cause injury to an occupant. In addition the occupant may, depending upon the size of the occupant and the adjusted seat position, also hit and contact various parts of the vehicle interior again resulting in injury.
To address these problems vehicle designers carefully design vehicle interiors and increasingly provide various ‘occupant protection’ systems. In particular airbags which automatically inflate in the event of a crash and which cushion an occupant are now common. Seat belts to restrain a seat occupant are also now compulsory in at least some countries, and may also include seat belt pretensioners.
Increasing adjustment of the seat and seat position is being demanded, with adjustment over increasing ranges to more comfortably accommodate different seat occupants. The increasing adjustability of vehicle seats, and so diverse and different position of the seat occupant, however presents a problem when designing such occupant protection systems and vehicle interiors. Specifically any occupant protection system must safely operate over the entire range of seat positions and for all different sizes of seat occupant. In addition airbags in themselves may cause injury to an occupant in particular if the occupant is positioned too close and/or not correctly siting within the vehicle.
It is therefore generally desirable to improve the occupant protection provided to a vehicle occupant, as well as address some of the above mentioned problems with conventional arrangements. In particular it is desirable to provide an improved adjustable vehicle seat which improves the protection provided to an occupant in the event of a crash.